Tip for cutting torches



July ll, 1950 D. A. MARRA TIP PoR CUTTING ToRcHEs Filed July 25, 1947 Marra "d flbtomwas zy. 2f am'em.

Patented July ll, 1950 UNITED STATES PATENT oFFicE TIP FORCUTTINGTORCHES Daniel A. Marra, Cheswick, Pa. Application July 25, 1947,Serial No. 763,520

s claims. (c1. 15s- 274) This invention relates to torch tips, andparticularly to the tips for cutting torches, and consists in certainnew and useful improvements in the multiple-part structure and in theparticular combination of materials for the component` 5 membersthereof.

In the accompanying drawings: Fig. 1 is a view in side elevation of acuttingtorch tip embodying my invention;

Fig. 2 is a View to larger scale of the rear or inlet end of the tip inelevation;

Fig. 3 a view of the front or delivery end of the tip in elevation, onthe same scale as Fig. 2;

Fig. 4 is a view of the tip in longitudinal and 'axial section; 1

Fig. 5 is a fragmentary view in side elevation of the stock from whichone component of the outer tip member is shaped;

Fig. 6 is a View in side elevation of the inner tip member, ready forassembly;

Fig. 7 is a fragmentary view in side elevation l of the stock from whichone component of the Fig. 10 is a view partly in axial section and v0`partly in side elevation, illustrating the progressive assembly, flrst,of the inner member with the inner componentof the outer member, and,

second, the assembly of the united parts last named with the outercomponent of the outer=35 member;

Fig; l1 is a view comparable with Fig. 8 illustrating` a modication ofthe inner component of the outer tip member.

A cutting tip is essentially a tubular article intimi whose wallsadditional passageways are formed. At the delivery end the centralorifice is surrounded by a ring of orifices through which thepassageways formed in the walls emerge. When the tip is assembled and inservice, heating flamesl45 spring from the ring of orices, and, atproper time, a jet of cutting oxygen is delivered from the centraloriiice.

It is entirely possible to form such a tip of an *l integral blank(ordinarily of copper), and to' 50 drill'through the solid metal all ofthe passage- Ways within the walls. But the expense involved is such,the slowness of production, and the dinicultyof producing accuratework,that the preva-w l lent way of producing cutting tips is to form them'55' and, third, an intermediate tip member 2|.

of two tubular parts telescoped together. It is usual to form the 'innerpart of brass, to sink into its outer surface suitable grooves, and totelescope upon the machined inner part an outer Asleeve of copper. Thisouter sleeve, overlying the grooves, completes the desired passageways.

Under the extreme temperatures and rough usage to which torch tips aresubjected in service, the tips in common use heretofore last Only Aarelatively short time, and the problem has al- Ways been to provide amore enduring structure, without increasing the cost of v'production toprohibitive degree.

-My solution of the problem consists in form- Iing the terminal andinner tip portions of a highly refractory and conductive metal. Moreparticularly, I have discovered that by forming these tip portions ofsuch .a metal, the outer l-tip member or sleeve may be formed of a mate-2 rial which is less refractory and conductive, such a relativelyinexpensive material `as malleable cast iron or a high chrome-nickelcast steel. The so-constituted structure provides a success- `ful andsuperiorl tip; and the quantity of copper required in the tip is muchless than the quanltity that goes into the typical brass-copper tip.

Indeed, in some cases the use of copper or cuprous vmetals may beeliminated.

A cuprous metal may be used for the inner tip v,member-and the metal maybe relatively pure copper, or it may be Monel metal, an alloy whosecopper component approximates 35%. I have found that a cuprous metal ofthe types mentioned has certain physical properties compatible tothoseof malleable cast iron under the condiy,tions of service towhichthe tip is exposed. The I sci-composed tip admits of ready fabricationand assembly, and the component parts mutually cooperate in affordingintegrity and durability of ltip structure under high temperature.

Referring to the drawings, the tip of my invention comprises threemembers: first, an outer tip member 3l; second, an inner tip member I I;The rst or outer `tube member is formed of tubular fsto'ck'of malleablecast-iron, as indicated at 3, i Fig. 9.y It is cut to length,counter-bored as indicated at 34, Fig. 10, machined to the exterior formrequired for seating in the head of a torch, and provided with drilledpassageways 35,

l through which, when the tip is seated, a gaseous mixture, or thecomponents of a desired gaseous "mixture, may flow from suitablepassageways in inthe torch, head 'to vthe counter-bored space 34. `Atv`the delivery end the stock will ordinarily be tapered, as indicated at36, and thus the outer member 3l is completed. At the basal end the bore33 in the outer member 3| corresponds to the outer diameter of thesecond or inner member Il, and the counterbore 34 corresponds to theouter diameter of the third or intermediate member 2 I Heretofore, ithas been customary to form the inner tip member of a brass or coppertube having an excessive 4wall thickness, and then to l0 machine theltube lexternally lthroughout the greater portion of its extent to areduced diameter, in order to provide, when the machined tube isassembled in the outer ti-p fmember, a

chamber between the inner and outer members, 15

from which chamber passageways lead lvto the delivery end of the tip. Asldistinguishedfrom such practice, l? form the second or inner 'tipmember II of a tube I of copper or Monel-metal.

The forming involves accurate cutting to length, 20

,aattenuationattheend that is to become the delivery -end I2 (withcorresponding chocking of .the bore, as shown in Fig. 4), and thesinking 'of' grooves I3 inthe surface at the attenuated end.

The third or intermediate tip member 2| is a 25 short essentiallyytubular member formed of {copper 'or Monel metal, telescoped upon theV.groovel end ofthe inner member I I. The mem- V:ber ZI Vis effective by:overlying the grooves I3 to Yconvert the grooves into passageways, andis .effective -by virtue of itsshort extent into the bore of theoutertip member torpermit the space between the inner and outer tipmembers to Aform aerelatively long gas chamber 31 Fig. v4. In Fig.

i?? tubular stock 2 'of copper or Monel metal is 35 illustrated, andfrom such `stock vthe lthird or intermediate member 2I (Fig. 8) of thetip is rformedby cutting and shaping. The bore of this `thi-rd membervis formed with a taper 24 that corresponds to the taper of the deliveryend I2 of d0 4the .inner .member II. The member 2l is applied tothedelivery end of the member I I and is telescoped upon it in a snug,hermetically tight, and lphysically Secure union (cf. Figs. 10 and 4).

The member I I, with which the member 2! has lalready been united, isintroduced into the member 3| through the counter-bored delivery end,and the parts Yare telescoped to the assembled positions shown in Fig.4. The Vtele-.5o

scopic unions at the basal and delivery ends are snug, hermeticallytight, and physically secure. n vthe mid-portion of their extent themembers 1I and SLI stand apart to form the chamber 31 that is closedrearwardly by the shoulder at the 5:5

. livery oriiices.

The .completed tip maybe of normal shape and proportionsand may serve innormal manner.

Beingseated in the yhead of .a torch, a combustible o5 .gaseous mixtureVdelivered through the passageways formed .by the grooves I3 may burn atthe delivery end in a circle of jets called the heating flame. This:dame may be caused to play upon .the

work until the Work is brought to the desired high 7 Cutting oxygenthen, delivered temperature. through the bore of member I I and playingupon the hot work produces localized combustionof the rsubstance of .thework, and such combustion proeffect the burning away of material that iscalled cutting.

Monel metal or copper may readily be worked in the manner and to theends described; it is of such high melting-point, such refractoriness,and such resistance to corrosion, as to render it a suitable materialfor cutting-torch tips.

Malleable cast iron could by no means be so used, for if the tip wereformed wholly of malzl'eable cast. iron,;it would in service fburnrapidly away 1anol'A-be destroyed. However, Aas already mentioned, Ihave discovered that if the inner Stip member be formed of another andless com- .bustiblemetaL specifically a cuprous metal, and

if, additionally, the third member ZI be provided Cfor-medalso of suchless combustible material), then the ,outer member SI (which thenbecomes really a case or shell) may successfully be formed of :malleablecast iron. The heat generated in the operation of a, torch is exertedmost intensely .upon'the deliveryend. of the tip at the very centre,.and frcmthatpoint diminishes outwardly in in- Itensity.; and I havefound by actualexperience that -in -the :tip 4here shown and describedthe -fouter.-member 3l -is at the delivery end so far remote from thecentre of heat intensity that it is not brought tothe temperature ofcombustion L,and destruction. Malleable cast iron is a material that,being -shaped to form the outer tip lmembersl, andbeing hardened,retains its hardness, unimpaired within the temperature range yofservice. And, .in the matter of hardness, an outer tipmember formed ofmalleable cast iron is tfar superior to such la member formed of copper(as is usual) for it will endure the rough usage 4.of seri/iemand willnotbecome nicked and mis- .shapen as a-copper member-does, and it willnot melt, as copper under severe -usage is apt to do. Malleablezcastironas a vmaterial for the outer tip member 3I is, .even in normaltimes, far lcheaper than copper.

-The parts VII .and 2l of the tip will not suffer serious distortion inlmaking assembly with the 4malleable castiron member 3|; and, in thematter Assembly is effected ln the manner illustrated 45 .of thermalexpansion, thecoeiiicients of the two parts are so nearly identical.that the assembled .structure continues secure and tight through all.the .range `of temperature incident to service.

It will be observed that in adapting a heatresistant ferrous metal touse in forming the greater portion `of va rblowpipe tip, minimum de-.parturefhasbeen made from conventional tip construction. .It rhas notbeen, -by virtue of the discovery .of my invention, necessary to fortifyor .enlarge .the body of .the tip at its outlet end, nor to vinterruptthe extent of the ferrous body portion of the tipat .a -substantialinterval from the outlet .end of 4the tip.

The multiple-part tip .structure designed to provide ,for Athe eiectiveuse of a ferrous metal rin the major portion `of the tip body admits ofthe advantageous :use of other materials not heretofore used rin tips inthe combination now to be considered.

The central and intermediate tip members II and 2l .may be formed of ahighly refractory 0 denum, uranium, boron, aswell as the alloys andmixtures of such elements with each other and with iron. The particularmethod of fashioning and forming the parts and whether the material beknown vas cemented carbide or sintered carbide f grasses, withprogressing localized heating, to ,fml .are matters well `understood inthe metallurgical art, and need not be further dwelt upon in thisspecication directed to the torch tip art. Suffice it to say that in theappended claims where I use the word carbide, I intend to include thehard metallic composition of the class mentioned, whatever may be thespecic composition or the `method of its production.

The body of the central tip member need not be entirely formed of suchmetal. For example, the grooved delivery end portion only of member I Imay be formed ofthe sintered carbide and the remainder of the bodyofsuch member may be formed of another andless costly metal, the twoportions being welded or otherwise integrated end to end in a hermeticunion. Ihe tip thus constructed with its members Il and 2l comprised ofa sintered carbide is serviceable for many times the life of tipsas-constructed heretofore. f

In renement, the intermediate tip member 2| may be provided with anoutwardly extending ange or peripheral shoulder 2m, Fig. 1l, whichsnugly fits upon and overlies the edge of thev outer member or sleeve 3lat the delivery end of ythe tip, thus aiording protection and `greaterdurability. By virtue of the described use of a sintered carbide in theinner and intermediate tip members, it becomes possible and practical toform the outer tip member of aluminum or magnesium, or other light andrelatively soft or vulnerable material.

This application is a continuation-in-part of an application Serial No.526,553, filed by me March 15, 1944now abandoned.

Within the scope of the appended claims various modifications andvariations may be made without departing from thespirit of theinvention.

I claim:

1. A torch tip comprising an elongate inner member of tubular form whosebody at the delivery end of the tip is formed of a highly refractorymetal and is externally formed with a plurality of grooves extending inlongitudinal direction, an intermediate member less in length than theinner member and in the assembly overlying the grooved portion of theinner member and forming with the grooves gas passageways, and an outertubular member, formed of less refractory material, telescopicallyassembled with said inner and intermediate members and forming with thema gas chamber from which said gas passageways lead.

2. The structure of claim 1, wherein the intermediate member is alsoformed of a highly refractory metal.

3. The structure of claim 2, wherein the intermediate member includes aperipheral shoulder overlying the edge of said outer tubular member atthe delivery end of the tip.

4. The structure of claim 1, wherein the intermediate member includes aperipheral shoulder overlying the edge of said outer tubular member atthe delivery end of the tip. 4

5. 'I'he structure of claim 1, wherein the body of said central memberat its delivery end comprises sintered carbide.

6. The structure of claim l, wherein the body of said intermediatemember comprises sintered l carbide.

7. A tip for a cutting torch comprising an elongate inner member ofMonel metal of essentially tubular form externally formed with aplurality of grooves adjacent its delivery end, an intermediate memberless in length than the inner member and in the assembly overlying thegrooved portion of the inner member and forming with the grooves gaspassageways, and an outer member of malleable cast iron of essentiallytubular form, counter-bored from the delivery end toward the oppositeend and in the assembly enveloping both the inner and the intermediatemembers and forming with them a gas chamber from which the said gaspassageways lead.

8. Thetip of claim '7, wherein the intermediatey member is also formedof Monel metal.

` DANIEL A. MARRA.

REFERENCES CITED The following references are of record in the file ofthis patent:

` UNITED vSTATES PATENTS Number Name Date 1,194,769 Neagley Aug. 15,1916 1,481,800 Harris Jan. 29, 1924 1,483,467 Meden Feb. l2, 19241,762,166 Fauset et al. June 10, 1930 FOREIGN PATENTS Number Country sDate 653,831 Germany s Dec. 3, 1937

